不同升降轨返回方式下定点返回轨道窗口解析分析方法

Analytical analysis methods for point return orbit window under different ascending and descending return modes

月地返回任务是载人月球探测任务实施的最后环节,建立恰当的定点返回轨道窗口分析方法可为任务设计和分析提供支持。现有的定点返回轨道窗口分析方法难以适应不同升降轨返回方式,且无法给出窗口的存在性必要条件。首先在地心惯性系下通过球面几何分析了月球反垂点与地球着陆场之间的关系,建立了升轨返回、降轨返回和先升轨再降轨返回等不同返回方式下定点返回轨道窗口的解析计算方法。然后考虑最大航程角和最小航程角约束,推导了着陆场纬度与返回轨道倾角需要满足的存在性必要条件,并建立了月球反垂点位置的解析修正模型。最后对地球不同纬度着陆场和不同返回方式的轨道窗口进行了仿真分析,给出了返回轨道倾角和着陆场纬度的选取建议,相关结论可为未来载人月球探测总体任务规划提供参考。

The lunar return mission is the final stage of the manned lunar exploration mission,and the establishment of appropriate fixed-Point Return Orbit(PRO)window analysis methods can support mission design and analysis.The existing PRO window analysis method is difficult to adapt to different ascending and descending return modes,and the necessary conditions for the existence of the window cannot be given.Firstly,the relationship between the lunar anti⁃pode and the Earth's landing site is analyzed by spherical geometry under the geocentric inertial coordinate system,and the analytical calculation method for the PRO window is established under different return modes such as ascend⁃ing return,descending return,and ascending-descending return.Then,considering the constraints of the maximum and minimum flight path angle,the necessary conditions for the existence of the landing site’s latitude and the PRO’s inclination are formulated,and an analytical correction model is established for the position of the lunar antipode.Fi⁃nally,the orbital windows of the Earth's landing sites at different latitudes and under different return modes are simu⁃lated and analyzed,and suggestions for the selection of the PRO’s inclination and the landing site’s latitude are given.The relevant conclusions can provide reference for the overall mission planning of the manned lunar exploration mission in the future.